1. Field of the Invention
The present invention generally relates to a communication device connected to a network and an information processing apparatus, and a method of controlling the communication device. The invention may also generally relate to a storage medium and a program having computer-executable instructions for performing the method.
2. Description of the Related Art
In a network environment, there are often many printers having different functions and capabilities. In this case, the following issue may arise: some of the newer printers in the network environment may support a secure printing function, while the older printers do not.
According to a proposed approach, a network card device connectable to an existing printer through an interface may be used. The network card device is capable of adding a function to the existing printer.
Japanese Patent Laid-Open No. 2005-038011 discloses an intelligent network card device including a CPU. This network card device is used while being connected to the main body of a printer. Typically, the network card device supports a print server function for performing centralized control of various print services via a network. The printer communicates with the network card device through an interface to provide a service.
In some cases, the network card device uses the same network address (e.g., IP address) as that of the printer. In this case, the network card device is disposed at the front end of the printer as viewed from the network side. The printer and the network card device are recognized as a single communication apparatus by other communication apparatuses existing on the network.
Accordingly, a service, such as the print server function, supported by the network card device, can be recognized as an expanded service added to the printer itself. Furthermore, existing services, which are not provided by the network card device and are originally supported by the printer, can function as before without being affected by the presence of the network card device.
In addition, to achieve the above-described provision of services, the network card device has a function of, when receiving a communication packet from another communication apparatus existing on the network, determining whether the packet relates to a service supported by the network card device itself.
When determining that the received packet relates to the service supported by the network card device, the device processes the packet by itself to execute the service related to the packet. Whereas, when the received packet does not relate to any service supported by the network card device, the device transfers the packet to the printer through the interface. The printer executes a service related to the transferred packet.
In recent years, printers having a filtering function for communication have been developed. According to the filtering function, filtering information is previously registered in the printer by a user, such as a network administrator. When the printer receives a communication packet from a communication partner which matches the description of the filtering information, the packet is discarded by the filtering function. Alternatively, the filtering function allows the printer to receive a communication packet from a communication partner which matches the description of the registered filtering information and discards a communication packet sent from another communication partner. The filtering information can be set through an operation panel provided for the printer.
Typically, either or both of a physical address and a network address are used as the above-described filtering information. More specifically, in the TCP/IP protocol, a media access control (MAC) address is used as the physical address and an IP address is used as the network address.
It is assumed that the above-described network card device is attached to a printer which denies access to a service supported by the printer from a predetermined communication apparatus existing on the network using the above-described filtering function. In this case, since the network card device is positioned at the front end of the printer as described above, the filtering function is not applied to a service supported by the network card device itself.
Thus, the communication apparatus which is denied access to a service supported by the printer may nonetheless be able to access a service supported by the network card device.
A method for allowing the network card device to have a filtering function that is similar to that of the printer has been proposed. In this case, however, the user may have to again set similar filtering information in the network card device in the same way as in the printer.
Accordingly, in some cases, the user may have to previously grasp the filtering information in the printer. Alternatively, the user may have to set filtering information, having the same description as that of the filtering information in the printer, in the network card device with reference to the filtering information in the printer. Such a setting operation may be complicated for the user. Also, in some cases, a setting error may easily occur. In addition, the network card device may have to include a unit, such as an operation panel, in order to set filtering information in the same case as the printer.
A method disclosed in Japanese Patent Laid-Open No. 2005-354410 has also been proposed. Specifically, according to the method disclosed in Japanese Patent Laid-Open No. 2005-354410, a host located at the back end communicates with a router at the front end using a predetermined multicast address. During communication therebetween, the host transmits filtering information set therein to the router. The router receives the filtering information and sets the information therein.
To realize the above-described method, the host may have to have a function of notifying the router of the filtering information set in the host using the predetermined multicast address. Accordingly, when a host without the above-described function and a router are used in combination, it may be necessary to individually set filtering information.